We have developed a screening procedure for transforming growth factor activity in the urine. Analysis of acid extracts of urine from normal donors and cancer patients by reverse phase HPLC revealed the presence of five EGF-related growth factors with soft agar colony promoting activity. In addition, factors were identified for the first time in urine which had colony stimulating activity only in the presence of EGF, but which were not EGF-related. Determination of EGF activity and quantitation of levels of EGF activity were accomplished using a solid phase radioreceptor assay developed in this laboratory this past year. Of the EGF-related activities observed using this assay, two were elevated in cancer patient urines, one of which correlated with a high molecular weight IGF previously shown by gel filtration to be unique to most cancer patients. Another TGF was found at high levels in normal control urines. Thus, using reverse phase HPLC, we were able to resolve five major species of EGF-related TGF. These are functionally similar, but chemically distinct from TGF isolated from tissue culture tumor cells. Distinct qualitative and quantitative differences are seen in TGF urinary moieties of cancer patients compared to normal controls. Purification methods are being developed to allow isolation of the tumor-associated urinary TGF in sufficient quantities to allow complete biochemical characterization and comparison to TGF produced by tumor cell lines in tissue culture.